## What did Hipparchus discover in astronomy?

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Hipparchus of Nicaea (/hɪˈpɑːrkəs/; Greek: Ἵππαρχος, Hipparkhos; c. 190 – c. 120 BC) was a Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of precession of the equinoxes.

### What is Hipparchus most famous for?

Solar and lunar theory. Hipparchus’s most important astronomical work concerned the orbits of the Sun and Moon, a determination of their sizes and distances from Earth, and the study of eclipses.

**How did Hipparchus influence astronomy?**

A Greek mathematician and astronomer, he measured the earth-moon distance accurately, founded the mathematical discipline of trigonometry, and his combinatorics work was unequalled until 1870. Hipparchus discovered the precession of the equinoxes and observed the appearance of a new star – a nova.

**What did Claudius Ptolemy discover?**

Ptolemy made contributions to astronomy, mathematics, geography, musical theory, and optics. He compiled a star catalog and the earliest surviving table of a trigonometric function and established mathematically that an object and its mirror image must make equal angles to a mirror.

## Why is Hipparchus called father of trigonometry?

The first known table of chords was produced by the Greek mathematician Hipparchus in about 140 BC. Although these tables have not survived, it is claimed that twelve books of tables of chords were written by Hipparchus. This makes Hipparchus the founder of trigonometry.

### Who was the first true astronomer?

Galileo Galilei was among the first to use a telescope to observe the sky, and after constructing a 20x refractor telescope. He discovered the four largest moons of Jupiter in 1610, which are now collectively known as the Galilean moons, in his honor.

**How did Hipparchus discover trigonometry?**

He did this by using the supplementary angle theorem, half angle formulas, and linear interpolation. Hipparchus was not only the founder of trigonometry but also the man who transformed Greek astronomy from a purely theoretical into a practical predictive science.

**What is Claudius Ptolemy best known for?**

Key facts. Claudius Ptolemy was a 2nd century Greek mathematician, astronomer and geographer famous for his controversial geocentric theory of the universe, which would form the basis of our understanding of the motions of stars and planets for over than a thousand years.

## What did Claudius Ptolemy do for astronomy?

Ptolemy synthesized Greek knowledge of the known Universe. His work enabled astronomers to make accurate predictions of planetary positions and solar and lunar eclipses, promoting acceptance of his view of the cosmos in the Byzantine and Islamic worlds and throughout Europe for more than 1400 years.

### Who discovered sin?

Sine was introduced by Abu’l Wafa in 8th century, as a more convenient function, and gradually spread first in the Muslim world, and then to the West. (But apparently it was used in India centuries before him), as a more convenient function. However this new notation was adopted very slowly, it took centuries.